How to Make a Liquid Barometer

Barometers are used for charting the rise and fall of atmospheric pressure--whereas rising pressure is a sign of dry and gentle weather to come, falling pressure can signal a coming storm.

But these instruments are as simple as they are useful, and come in a wide variety of forms, which means that anyone can make their your own barometer out of household items. Read on to learn how to make a liquid barometer.

Place a small ruler inside of your jar. Affix it to the inside of the neck with modeling clay.

Fill the jar with a few inches of isopropyl alcohol.

Place a straw into a bottle of isopropyl alcohol, so that the straw is half-submerged, and then plug the top end of the straw with modeling clay to form a seal. Afterwards, remove the straw.

Place the straw inside the jar, next to the ruler, and set it into place with clay. The bottom of the straw should enter the pool of isopropyl alcohol, but without touching the bottom of the jar.

Measure the level of alcohol in the straw daily. Rising atmospheric pressure will force down the alcohol in the jar while sending it up the straw, and vice versa.

Things You Will Need

  • Small glass jar
  • Ruler
  • Modeling clay
  • Isopropyl alcohol
  • Straw

Tip

  • Try to leave the jar in a place that is neither too sunny, nor too drafty.

Warning

  • Do not totally fill the neck of your jar with clay, as this will close your barometer off from the atmosphere.